Carbon nanotubes are tubules of carbon generally having a diameter of about 0.5 to about 100 nanometers, and composed of a number of coaxial cylinders of graphite sheets. Carbon nanotubes along their axial directions have interesting and potentially useful thermal, electrical, and mechanical properties, and have recently attracted a great deal of attention for use in different applications such as field emitters, thermal and electrical conductors, and high strength composites. A carbon nanotube array is grown on a flat surface of a silicon wafer by using a chemical vapor deposition (CVD) method and has the carbon nanotubes aligned along a direction substantially perpendicular to the flat surface of the silicon wafer. The excellent axial properties of the carbon nanotubes can be easily used by using the carbon nanotube array.